Hello again, I'm terribly sorry for the double post. Claus, you might try detecting the speed of the connection and re-enumerating if necessary. It would avoid noncompliance with the spec and is probably the easiest option.
Unsure of how this would be done with a C manifestation of functionfs code but echoing "" to the UDC pseudofile under /sys/kernel/config/usb_gadget/${your_gadget} will allow you to set everything up again and reenumerate.
On Tue, May 12, 2020, at 11:43 PM, Sid Spry wrote:
> Have you tried only providing a SS configuration? If that fails for some reason I suspect the next course of action would be to see why, and patch the driver so it does not.
>
> Out of curiosity, which SoC are you using?
>
> On Tue, May 12, 2020, at 3:08 PM, Claus Stovgaard wrote:
> > On tir, 2020-05-12 at 15:52 -0400, Alan Stern wrote:
> > > On Tue, May 12, 2020 at 09:25:38PM +0200, Claus Stovgaard wrote:
> > > >
> > > > In a certain scenario I would like to force the dwc3 to only
> > > > connect
> > > > via superspeed and not fall back to USB2.
> > > >
> > > > What options exist for forcing the dwc3 to keep retry?
> > >
> > > The USB-3 spec forbids devices from operating only at SuperSpeed.
> > > Devices must be able to connect at high speed, although possibly
> > > with
> > > reduced functionality.
> > >
> > > Alan Stern
> > >
> >
> > I understand the requirement from the USB 3 specification. Though in
> > the scenario for this specific device, it is not about comply with the
> > USB 3 specification, but my question is rather what options I have for
> > not comply with the specification here, and then force retry of USB 3,
> > using the dwc3 as device.
> >
> > The device is in a fixed mounting with a fixed host. Sometimes when the
> > host and device is powered up, it ends in high-speed instead of super-
> > speed. I would like the option for "I will not be compliant with USB,
> > but rather retry super-speed".
> >
> > Regards
> > Claus
> >
> >
